A Reassessment of the Distribution of Multiple Sclerosis

Abstract

When reviewed some 10 years ago, available prevalence studies of multiple sclerosis (MS) seemed to divide the world into three frequency zones for MS: high prevalence at 30 to 60 per 100,000 population; medium at 5 to 15; and low at less than 5 per 100,000. In the last decade the number of the available studies has more than tripled. Their reassessment, including judgments of comparability, still indicates a high‐medium‐low division for MS frequency world‐wide. The high risk areas comprise northern Europe, northern United States, much of southern Canada, New Zealand, and probably southern Australia. Prevalence rates in these regions are mostly 30 to 80 per 100,000 population, centering at about $50. Medium frequency is defined as prevalence of 5 to 25, and is mostly 10 to 15. In Europe, the medium frequency zone bounds that of high frequency to the north, east, and south. The European Mediterranean basin is of medium prevalence with a sharp division from the high zone across France and Switzerland. It is likely that this division continues eastward across Austria, north of Hungary, and across the upper Ukraine to the Caspian Sea, but this is not definite. Medium risk areas of Europe thus include surveyed sites of Spain, Italy, Hungary, Jugoslavia, Bulgaria, and central Ukraine, together with southeastern France and southern Switzerland. Though Romania could be high, it is more likely to be of medium prevalence. Turkey measures low, but from incomplete data. From nationwide prevalence and mortality studies, the west coast of Norway and all Scandinavia above latitude 65° north are of medium frequency. Based on hospital data, northwestern USSR is high, and central and southern USSR medium, in MS risk. Other medium risk areas include southern United States, most of Australia, one ethnic group only in South Africa, and possibly Hawaii. Low risk areas are all surveyed sites of Asia, the Pacific islands, Africa, Latin America, Alaska, and Greenland.

Characteristics of Devic's disease (neuromyelitis optica) in Mexico

“…In Japan, the overall prevalence of MS in 1972 averaged 2 per 100,000 population [12]. The nationwide survey at that time by Kuroiwa et al [10] cited in Table 1 recorded 509 MS and 82 Devic's disease, both with strict diagnostic criteria, and this would then have provided a prevalence rate for NMO of 0.32 per 100,000 (95 % CI 0.26-0.40).…”

Epidemiology of Multiple Sclerosis in Iran: A Systematic Review

“…Nevertheless, in order to show the overall pattern of MS in Iran, we also investigated unpublished data on the prevalence of MS from local MS registries across the country and presented them in line with previously reported data. Figure 1 indicates that Iran is an intermediate- to high-risk region and the bulk of studies in different provinces have rejected the geographical distribution hypothesis [2,32]. …”

Multiple Sclerosis in Iran: A Demographic Study of 8,000 Patients and Changes over Time

“…Based on the Kurtzke classification, Iran is located in a low-risk zone for MS [5,6,10. ]However, recent studies on the prevalence of MS came up with different results and indicated a higher prevalence rate in this country [11,12.]…”

“…Kurtzke [5,6 ]divided the world into three categories considering MS prevalence. According to his classification, the prevalence of 30 or more per 100,000 of a population is defined as a high risk, 5–29 as a medium risk and less than 5 as a low risk zone.…”